VxFS processes two basic types of file system I/O:
In the case of sequential I/O, the VxFS employs a read-ahead policy by default, if the application is reading data. For writing, it tries to allocate contiguous blocks if possible. In most cases, VxFS handles I/O that is sequential through buffered I/O. VxFS handles I/O that is random or not sequential directly without buffering through direct I/O.
VxFS provides a set of I/O cache advisories for use when accessing files.
See the Veritas File System Programmer's Reference Guide.
See the vxfsio
(7) manual page.